Another vital source of error comes from calibration of the low-frequency data. Meticulous research has shown that minute errors in instrumental calibration affect the separation of signals from the bright foreground emission. The basic equation for calibration (assuming implicit time and frequency dependence) is thus given by [1]}:
\({V}_{ij}^{obs} = g_{i}g_{j}^{*}V_{ij}^{true} + n_{ij}\) 
